How to bind an object to a table

[bumperman_jc]

Hi,

I am new to .net. I think .NET provides what I need, but I don't
know how to implement it.

What I need is simply associating an object with a database
table. I would like to load "objects" from table, and I would like to
modify or delete objects, without dealing with database in anywhere. In
other words; I do not want to write SQL query for any of those
operations. Let me give you an example (in C++/CLI):

ref class MessageBase abstract
{
String^ m_strFrom;
String^ m_strBody;
String^ m_strSubject;
DateTime m_dtRecSent;
DateTime m_dtReplied;
DateTime m_dtForwarded;
MessageTypes m_mtType;
public:
property String^ From { String^ get(); void set(String^); }
property String^ Body { String^ get(); void set(String^); }
property String^ Subject { String^ get(); void set(String^); }
property DateTime ReceivedDate { DateTime get(); void
set(DateTime); }
property DateTime RepliedDate { DateTime get(); void
set(DateTime); }
property DateTime Forwarded { DateTime get(); void set(DateTime);
}
property DateTime SentDate { DateTime get(); void set(DateTime); }
property MessageTypes MessageType { MessageType get(); void
set(MessageTypes); }
};

I have got a table to store this information. I would like to
load "messages" from table at startup, through a factory (another
recommendation?). I have prepared a typed dataset, too, but I couldn't
associate it with this class. What I have done previously in C++ was a
simple adapter. Adapter was acting like a "message object" to the
application itself, any changes in the object automatically goes
database, too. As far as I have heard, after associating this class
with a table, I will not write any SQL statement.

I would be very happy, if you could enlighten me about this type
of association. I am using .NET Framework 2.0 (of course, since I am
using C++/CLI) and I do not have a performance concern with this
operation (I have heard that this type of association of an object with
a dataset is far slower than SqlDataReader way). Database is SQLite, I
am using ADO.NET class library to access database from .NET (I have
native library as well).

Thanks!
Jason

 

[Cor Ligthert [MVP]]

Bumperman,

There are hundreds of types of tables in Net, I assume now that you mean a
database table.

An object is the rawest part of Net. In fact the base class for all other
types. Not really the one for binding. It has not any property that you can
bind.

http://msdn.microsoft.com/library/d.../cpref/html/frlrfsystemobjectmemberstopic.asp

However I assume that you mean an from Object inherited ObjectType. From
that you can bind all properties if the mechanisme is made in the consuming
type.

I will not write any SQL statement.

Do you mean write explicitly and implicitely. Than it is impossible. .Net
and SQL are working thight together where Transact SQL is used.

I would be very happy, if you could enlighten me about this type
of association. I am using .NET Framework 2.0 (of course, since I am
using C++/CLI) and I do not have a performance concern with this
operation (I have heard that this type of association of an object with
a dataset is far slower than SqlDataReader way). Database is SQLite, I
am using ADO.NET class library to access database from .NET (I have
native library as well).

The SQLDataReader is fairly quicker than using the SQLDataAdapter, which is
in fact a class holding a lot of methods to create, update, remove, select
dataobjects for you (datatable/dataviews, datasets, datarows). Those
dataobjects and the dataadapter have all kind of methods build in. One of
those methods in the dataadapter is using is the datareader.

I hope this gives some ideas

Cor

 

[Jason]

Bumperman,

There are hundreds of types of tables in Net, I assume now that you mean a
database table.

An object is the rawest part of Net. In fact the base class for all other
types. Not really the one for binding. It has not any property that you can
html/frlrfsystemobjectmemberstopic.asp

However I assume that you mean an from Object inherited ObjectType. From
that you can bind all properties if the mechanisme is made in the consuming

Do you mean write explicitly and implicitely. Than it is impossible. ..Net
and SQL are working thight together where Transact SQL is used.


The SQLDataReader is fairly quicker than using the SQLDataAdapter, which is
in fact a class holding a lot of methods to create, update, remove, select
dataobjects for you (datatable/dataviews, datasets, datarows). Those
dataobjects and the dataadapter have all kind of methods build in. One of
those methods in the dataadapter is using is the datareader.

I hope this gives some ideas

Cor

Cor,

thank you for your reply.

I assume now that you mean a
database table.
Yes.

An object is the rawest part of Net. In fact the base class for all > other
types. Not really the one for binding. It has not any property that
you can bind.

Either you misunderstood my concern, or, I have failed to chose the
right words. "How to bind an object to a table", doesn't mean type of
object is System.Object (look closer, System."O"bject, capital letter).
Besides this title, I have provided a sample class, which is a "type" of
an "object" (meaning in OOP, not in "C#") that I want to bind to table.
As you can see, it's got properties. By other means, it doesn't mean
anything whether C# uses "object" type for CTS type System.Object, which
begins with capital letter. In fact, only in .NET and Java, all
(managed) objects derive from the same class, but in OOP, an "object" is
not a System.Object, nor it is what C# and its programmers understand
from "object". "class" keyword defines a type. When you instantiate a
type of T, declared with "class", it becomes an "object of type T", and
it's got nothing to do with System.Object. In C++, we have bare "class"
keyword that declares a "native" class and it doesn't necessarily derive
from anything. I hope we are clear at this point, and you've refreshed
"what 'object' word means in OOP".

I am not unfamiliar with C#, I am not unfamiliar with .NET, I am neither
a student nor a 5 years experienced software developer. I know a couple
of ways to do this, typed dataset or NHibernate, or former Object Spaces
(LinQ?). NHibernate does what I need, but NHibernate is complicated,
error prone, takes a lot of time. I need a "typed dataset like"
solution.

Do you mean write explicitly and implicitely. Than it is
impossible. .Net
and SQL are working thight together where Transact SQL is used.

I do not want to write any SQL statement "explicitly". How can I write
SQL statements implicitly? If they are "implicit", doesn't it mean they
are not written by me? In .NET, you can retrieve data from a dataset
without writing even a single line of SQL statement(ReadXml, WriteXml?).

The point is; something like NHibernate, but simpler and preferably
integrated to IDE. Do you know/have a solution?

Jason

TLD LY is Libya, (just in case you may wonder "what the...") though, I
am not related to Libya.

 

[Cor Ligthert [MVP]]

Jason,

I think that there is nothing to add to your reply.

Cor

 

[dperiwal]

Jason,

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-- Damodar Periwal
===============================
Software Tree, Inc.
Simplify Data Integration
http://www.softwaretree.com